The present invention relates to a method for centrally managing plural storage devices.
In recent years, a technique for connecting a computer and plural storage devices by way of a network (storage area network (SAN)) and centrally managing the plural storage devices connected to the SAN has been proposed.
As a method for managing plural storage devices connected to a SAN, there is a technique for centrally managing a storage device (volume), among the plural storage devices connected to the SAN, as a storage pool, and efficiently using the memory capacity of the storage device connected to the SAN.
In a conventional system, capacity is added, by on-demand from a storage pool, when the volume capacity become short due to insufficient estimation of the capacity being used, at an insufficient time point. (For example, see (Patent Literature 1) JP-A-2002-222061 at p. 9, FIG. 11).
It is difficult to accurately estimate the capacity utilization in advance and to allocate the needed volume. In the past, when the capacity utilization (data capacity) was not increased as estimated, an unused storage area would remain and never be used.
In an environment in which storage devices are intensively consolidated and many volumes exist, it will happen that many unused and useless storage areas remain unused. Since such unused storage areas in volumes are unused, but cannot be utilized as the storage pool, the storage resources can not be efficiently used.